some of you may have missed this thread, im trying to figure out exactly why my enigne felt the need to destroy it self. Im thinking it was due to rod failure.

what happened was we had been tuning all night and ifnishe dthe ve and pe tables. we then moved to the spark table . this was after addign 5 degrees of timing at lower rpms . it died at 5k rpms with around 10 psi, 11.8 afr, off a first gear launch. the truck completley shut it self off and showed no knock retard at all.

lets hear some theories.

LINK to thread

 

Post up the log and config and tune. The rods in these puppies are tough. Pistons are much more prone to failure.

 

WOW, maybe the added timing on the low end created a lot more heat and once it got wound up a bit BOOM? Dunno man that sucks. I do know that sometimes when timing is too high, you may not be getting any KR but there is a lot of unecessary heat being created.

 

I've been running better than 17* timing for a long time at near 10 psi. I also have a lower compression engine though.

Looked at the carnage.... damn that sucks! Was that #7?

 

That's what I'm wondering about, the LQ9 is what, 10:1? And on top of that 10 psi and 17* timing. What were the timing values in the areas you added the 5*?

 

17* of timing was probably just too much for the airmass in the cylinder at the time and it detonated. What octane were you running when it croaked?

Also, where is your wideband located? Which bank of cylinders typically runs leaner via your Narrowband voltages?

 

i added the files

running 91 octane. wide band is on the passenger side.

the driver side is the side the croaked.

 

91 octane... 17* of timing with 10psi... What kind of timing did you run in the past? I can't read HPT logs, what was your peak airmass just before it went?

 

Did you add 5 degrees all at once? Where exactly did you add it? Even in part throttle thats a pretty big jump to make in one step.
Have you pulled the motor apart yet? What let loose?


Edit:.. Just read your other post.

17 deg is not "too much" for 10psi, its high, but not unheard of for some engines to like such timing. I think what happend in this case is detonation pure and simple. Finding optimal spark advance is a balance between positive and negative work.. What I mean is the amount of cylinder pressure is a determined by burn angle, spark advance, and peak pressure, fire too soon and peak pressure happens before TDC and you have major problems.

Next time I would reccomend adding timing at no more than 1.5 degrees at a time.

 

you can get them here at hptuners topic

http://www.hptuners.com/forum/showth...8923#post68923